The threat of biological and chemical warfare has grown considerably in recent times. Numerous countries are capable of developing deadly biological and chemical weapons. Some potent biological warfare agents include the following: bacteria such as Bacillus anthracis (anthrax) and Yersinia pestis (plague); viruses such as variola virus (small pox) and flaviviruses (hemorrhagic fevers); and toxins such as botulinum toxins and saxitoxin. Some potent chemical warfare agents include: blister or vesicant agents such as mustard agents; nerve agents such as methylphosphonothiolate (VX); lung damaging or choking agents such as phosgene (CG); cyanogen agents such as hydrogen cyanide; incapacitants such as 3-quinuclidinyl benzilate; riot control agents such as CS (malonitrile); smokes such as zinc chloride smokes; and some herbicides such as 2,4-D (2,4-dichlorophenoxy acetic acid).
All of the above agents, as well as numerous other biological and chemical agents, pose a significant risk to private citizens as well as to military personnel. For example, vesicant agents burn and blister the skin or any other part of the body they contact, including eyes, mucus membranes, lungs, and skin. Nerve agents are particularly toxic and are generally colorless, odorless, and readily absorbed through the lungs, eyes, skin, and intestinal track. Even a brief exposure can be fatal and death can occur in as quickly as 1 to 10 minutes. Biological agents such as anthrax are easily disseminated as aerosols and thus have the ability to inflict a large number of casualties over a wide area with minimal logistical requirements. Many biological agents are highly stable and thus can persist for long periods of time in soil or food.
There are currently two general types of decontamination methods for biological agents: chemical disinfection and physical decontamination. Chemical disinfectants, such as hypochlorite solutions, are useful but are corrosive to most metals and fabrics, as well as to human skin. Physical decontamination, on the other hand, usually involves dry heat up to 160° C. for 2 hours or steam or super-heated steam for about 20 minutes. Sometimes UV light can be used effectively, but it is difficult to develop and standardize for practical use.
These methods have many drawbacks. The use of chemical disinfectants can be harmful to personnel and equipment due to the corrosiveness and toxicity of the disinfectants. Furthermore, chemical disinfectants result in large quantities of effluent which must be disposed of in an environmentally sound manner. Physical decontamination methods are lacking because they require large expenditures of energy. Both chemical and physical methods are difficult to use directly at the contaminated site due to bulky equipment and/or large quantities of liquids which must be transported to the site. Finally, while a particular decontamination or disinfection method may be suitable for biological decontamination, it is generally not effective against chemical agents. There is a need for decontamination compounds which are effective against a wide variety of both chemical and biological agents, have low energy requirements, are easily transportable, do not harm skin or equipment and employ small amounts of liquids with minimal or no effluent. Such decontamination compounds may be useful in both military and commercial arenas such as first responders and the Heating Ventilation and Air Conditioning industry.
Because of the unique architecture of dendrimers, they have been investigated for a wide variety of applications, such as gene delivery vesicles, Tang, et al., Bioconjugate Chem., 7 at 703-714 (1996); Kukowska-Latallo, et al., Proc. Natl. Acad. Sci. USA, 93 at 4897-4902 (1996), catalysts, Zeng, F. Z., S. C. Chem. Rev., 97 at 1681 (1997); Newkome, et al., Chem. Rev., 99 at 1689-1746 (1999), drug delivery carriers, Liu, M.; Frechet, J. M., J. Proc. Am. Chem. Soc. Polym. Mater. Sci. Engr., 80 at 167 (1999); Uhrich, K., TRIP, 5 at 388-393 (1997); Liu, H.; Uhrich, K. Proc, Am. Chem. Soc. Div. Polym. Chem., 38 at 1226 (1997), chromatography stationary phases, Matthews, et al., Prog. Polym. Sci., 23 at 1-56 (1998), boron neutron capture therapy agents, Newkome, et al., Dendritic Macromolecules: Concepts, Syntheses, Perspectives; VCH: Weinheim, Germany (1996); Newkome, O. R., Advances in Dendritic Macromolecules; JAI Press. Greenwich, Conn., Vol. 2 (1995), and magnetic resonance imaging contrast agents, Tomalia, D. A. Adv. Mater., 6 at 529-539 (1994), all of which are herein incorporated by reference. Some examples of commercially available hyperbranched polymers include hyperbranched polyethylene imine (PEI) and Hybranes® (www.hybrane.com (DSM)).
Synthesized quaternary ammonium functionalized poly(propyleneimine) dendrimers have been evaluated with regard to their antibacterial properties. Bioluminescence results have confirmed that dendrimer biocides with 16 quaternary ammonium groups on their surfaces are over two orders of magnitude more potent than monofunctional counterparts against gram-negative bacteria, such as Escherichia coli. These biocides are also very effective against Gram-positive bacteria such as Staphylocoecus aureus, which are usually more susceptible to antimicrobials due to their less complex structures.